Epicyclic gearing with a gearing housing

ABSTRACT

A planet stage of an epicyclic gearing includes a gearing housing with a ring gear arranged in a fixed position, at least two planet wheels mounted in a planet web that has at least one cheek, and a sun wheel. The planet web is connected to an input shaft, and there is a connection between the input shaft and a component of a further planet stage. The planet stage of the epicyclic gearing, in particular the planet web, has a reduced torsional loading. The reduced torsional loading is achieved in that the connection is a connecting web which is connected to that cheek of the planet web which is acted upon by an admission of load/moment, and is arranged in the region between two planet wheels and within the ring gear.

The invention relates to a planetary stage of a planetary gear mechanismhaving a gear mechanism housing, in which a fixedly arranged internalgear, at least two planetary gears which are mounted in a planet spiderwhich has at least one cheek, and a sun gear are arranged, the planetspider being connected to an input shaft, and there being a connectionbetween the input shaft and a component of a further planetary gearmechanism.

A planetary gear mechanism of this type having a plurality of planetarystages is known from WO2008/104258 A1. The planetary gear mechanism isdesigned for a wind power plant which converts kinetic energy of thewind into electrical energy and feeds it into a power network. Theplanetary stages of the planetary gear mechanism interact with oneanother, a division of load taking place from a rotor shaft to a firstplanetary stage and, around the outside of the internal gear of thefirst planetary stage, to a second planetary stage. This configurationenlarges the overall volume of the planetary gear mechanism andtherefore increases the weight of the planetary gear mechanism as aresult of the necessary solid configuration. In addition, the runningbehavior of the planetary gear mechanism is influenced in adisadvantageous manner as a result of the high masses which are to bemoved.

A further planetary gear mechanism is known from EP 1 240 443 B1. Saidplanetary gear mechanism likewise has a first planetary stage which isconnected to a rotor shaft, in which first planetary stage the planetspider of the first planetary stage is connected to the internal gear ofa second planetary stage. This embodiment is generally customary and isused in planetary gear mechanisms which are installed, for example, inwind power plants.

The invention is based on the object of providing a planetary stage of aplanetary gear mechanism, in which the torsion loading of a planetspider of the planetary stage is reduced.

This object is achieved by virtue of the fact that the connection is aconnecting web which is arranged in the region between two planetarygears and within the internal gear and is connected to the cheek of theplanet spider, which cheek is loaded by an introduction of load/torque.In this embodiment, the load which is to be transmitted to a furtherplanetary stage is guided as a result past the planet spider of thefirst planetary stage in the region between two planetary gears and istransmitted to the further planetary stage. As a result, firstly no loadrouting around the internal gear of the first planetary stage isnecessary, and the first planet spider is loaded only by its own torsionwhich leads at least to reduced tilting and/or oblique positioning ofthe planetary gear bolts of the first planetary stage.

In one development of the invention, the number of connecting webscorresponds to the number of planetary gears. In particular, the firstplanetary stage of the planetary gear mechanism has three planetarygears, and three connecting webs are correspondingly provided betweenthe planetary gears within the internal gear. This configuration hasproven particularly suitable for connecting the second planetary stageto the first planetary stage.

In a further embodiment of the invention, the connecting web isconfigured in one piece with that cheek of the planet spider which isloaded by the introduction of load/torque. The planet spider and theconnecting web or the connecting webs are preferably configured as asingle-piece cast part, it being possible for the connecting webs to beproduced by way of a simple modification of the corresponding castingmould.

In a further embodiment of the invention, a division of load/torque tothe connecting web and to the planet spider or to the opposite cheek ofthe planet spider takes place in the cheek which is loaded with theintroduction of load/torque. If, for example, the planetary stage ispart of a wind power plant gear mechanism, as will be explained in thefollowing text, the cheek which is loaded by the introduction ofload/torque is connected to the rotor side and the opposite cheek isconnected to the generator side of the wind power plant (in each case ifrequired via further gear mechanism stages or planetary stages). Insummary, the division of load/torque according to the inventiontherefore takes place within the internal gear diameter of the planetarystage, as it were in the “empty spaces” between the planetary gears, anddoes not enlarge the overall volume.

In one development of the invention, the connecting webs are connectedto a connecting ring. The connecting ring can be configured as acontinuous closed ring or else as an interrupted ring in the form ofring segments. The connecting ring is correspondingly arranged on theopposite side to the cheek which is loaded by the introduction ofload/torque, and, for unproblematic assembly, has an external diameterwhich is smaller than the internal diameter of the internal gears of thefirst and also the second planetary stage. The assembly of the planetarygear mechanism with the individual planetary stages is therefore notimpeded in any way. The connecting ring with a total of three connectingwebs is preferably configured as a single-piece cast part, whereby theinput shaft, the planet spider (with the two cheeks), the connectingwebs and the connecting ring are therefore configured in oneparticularly advantageous embodiment as one component in the form of amachined cast part.

In one development of the invention, the connecting web or theconnecting ring is connected to an internal gear or a planet spider ofthe further planetary stage via a positively locking or frictionalconnection, in particular via a plug-in connection. A connection of thistype contributes to unproblematic assembly of the individual gearmechanism stages, it being possible for the latter to be arranged, forexample, in independent housing components.

In a further embodiment of the invention, the plug-in connection isconfigured as an externally toothed ring which is formed on theconnecting ring and as an internally toothed ring which is arranged onthe internal gear or the planetary gear carrier. This combination hasproven particularly suitable, both the production and the assembly beingsimplified as a result.

In one development of the invention, the planetary gear mechanism havingthe planetary stage which is configured according to the invention is acontinuous flow power plant gear mechanism, in particular an oceancurrent power plant gear mechanism or a wind power plant gear mechanism.A wind power plant is particularly preferably equipped with a wind powerplant gear mechanism of this type.

Advantageous developments of the invention can be gathered from thedescription of the drawing, in which one exemplary embodiment of theinvention which is shown in the figures is described in greater detail.

In the drawing:

FIG. 1 shows a side view of a wind power plant having a gear mechanismwhich has a planetary stage, configured according to the invention, of aplanetary gear mechanism,

FIG. 2 shows an end-side sectional illustration of a planetary stagewhich is configured according to the invention, and

FIG. 3 shows a cross section through a planetary stage which isconfigured according to the invention.

FIG. 1 shows a side view of a wind power plant 1 with its essentialassemblies. The wind power plant 1 has a tower 2, on which a nacelle 3,in the form of a machine housing, which is mounted such that it can berotated about a vertical axis, is arranged. A gear mechanism 4 isfastened in a rotationally fixed manner in the nacelle 3, the gearmechanism 4 having a drive shaft 5 and an output shaft 6. The driveshaft 5 of the gear mechanism 4 is connected to a hub 7 of a rotor whichhas a plurality of rotor blades 8. The output shaft 6 is rotationallyconnected to a drive apparatus to be driven in the form of a generator9. The gear mechanism 4 is designed in such a way that it converts aslow rotational movement of the drive shaft 5 into a rapid rotationalmovement of the output shaft 6. Electrical energy is generated by meansof the wind power plant 1, by the rotor which is set in rotationalmovement by the wind introducing the rotational movement via the driveshaft 5 into the gear mechanism 4. The gear mechanism 4 has, inparticular, a planetary gear mechanism with a first planetary stage 10and a second planetary stage which are connected to a summing gearmechanism. The summing gear mechanism is connected to the output shaft6, optionally via a spur gear mechanism, and converts the rotationalmovement into a more rapid rotational movement. Finally, the rapidrotational movement is transmitted via the output shaft 6 to thegenerator 9 in order to generate power.

FIG. 2 shows an end-side sectional illustration of the planetary stage10 as a constituent part of the gear mechanism 4. The planetary stage 10has an input shaft 11 which is connected directly or via a spur gearmechanism to the drive shaft 5. The input shaft 11 is connected to aplanet spider 12, in particular is configured in one piece as a castpart. The planet spider 12 is of approximately annular configuration andhas a total of three bores 13 which are arranged on the circumference ofthe planet spider 12 and into which planetary gear bolts 14 (see alsoFIG. 3) are inserted. Planetary gears 15 are mounted on the planetarygear bolts 14 via planetary gear bearings 16 a, 16 b. The planet spider12 is composed of two cheeks 27 a, 27 b which are connected to oneanother. The cheek 27 a faces the introduction of load/torque (that isto say the rotor side), whereas the cheek 27 b faces the generator side.The cheeks 27 a, 27 b are connected via what are known as smallheart-shaped formations 17 which serve primarily for said connection ofthe cheeks 27 a, 27 b and secondarily for the supply of lubricant to thegearwheels which mesh with one another, namely an internal gear 23,three planetary gears 15 and a sun gear 18 (FIG. 3).

Connecting webs 19 which protrude through the planet spider 12 and thecheek 27 b are formed integrally on the cheek 27 a of the planet spider12. The connecting webs 19 are connected on the side of the cheek 27 bto a connecting ring 20 or are configured in one piece, preferably as acast part.

According to FIG. 3, the connecting ring 20 is provided with an externaltoothing system 21 which interacts with an internal toothing system 22,in particular of an internal gear of a second planetary stage which isnot shown in further detail. Here, the external toothing system 21 isconfigured in such a way that it can be plugged through the internalgear 23 of the first planetary stage 10. The internal gear 23 of thefirst planetary stage 10 is arranged in a rotationally fixed manner inthe housing of the gear mechanism 4 via a torque support 24. A firstbearing 25 a and a second bearing 25 b, in which the planet spider 12 orthe input shaft 11 is mounted, are arranged in the housing and thetorque support 24. If the input shaft 11 is moved rotationally, theplanetary gears 15 run on the stationary internal gear 23 and set thesun gear 18 in a rotational movement which is transmitted preferably toa summing gear mechanism, via a sun gear shaft 26. At the same time, theinternal gear of a second planetary stage is driven via the rotationallymoved input shaft 11 by way of the connection according to theinvention, which internal gear has a stationary planetary gear carrier.In the second planetary stage, correspondingly, a rotational movement isexerted on a sun gear of the second planetary stage which is likewiseconnected to the summing gear mechanism. Here, the sun gear of thesecond planetary stage is connected to a hollow shaft of the summinggear mechanism, whereas the sun gear 18 of the first planetary stage 10is connected to a planetary gear carrier of the summing gear mechanism.

The summed rotational movement is correspondingly output via a sun gearof the summing gear mechanism to the output shaft 6.

LIST OF DESIGNATIONS

1 Wind power plant

2 Tower

3 Nacelle

4 Gear mechanism

5 Drive shaft

6 Output shaft

7 Hub

8 Rotor blade

9 Generator

10 Planetary stage

11 Input shaft

12 Planet spider

13 Bore

14 Planetary gear bolts

15 Planetary gear

16 a, 16 b Planetary gear bearing

17 Small heart-shaped formation

18 Sun gear

19 Connecting web

20 Connecting ring

21 External toothing system

22 Internal toothing system

23 Internal gear

24 Torque support

25 a, 25 b Bearing

26 Sun gear shaft

27 a, 27 a Cheek

1. A planetary stage of a planetary gear mechanism, comprising: a gearmechanism housing including a fixedly arranged internal gear, at leasttwo planetary gears mounted in a planet spider having at least onecheek, and a sun gear, the planet spider being connected to an inputshaft, and a connection between the input shaft and a component of afurther planetary stage, the connection being configured as a connectingweb which is arranged in the region between two planetary gears andwithin the internal gear and is connected to the cheek of the planetspider, the cheek being loaded by an introduction of load/torque.
 2. Theplanetary stage as claimed in claim 1, wherein the number of connectingwebs corresponds to the number of planetary gears.
 3. The planetarystage as claimed in claim 1, wherein the connecting web is configured inone piece with the cheek.
 4. The planetary stage as claimed in claim 1,wherein a division of load/torque to the connecting web and the cheek ofthe planet spider takes place in the cheek.
 5. The planetary stage asclaimed in claim 1, wherein the connecting web is connected to aconnecting ring.
 6. The planetary stage as claimed in claim 1, whereinone or more of the connecting web and the connecting ring is connectedvia a plug-in connection to an internal gear or a planetary gear carrierof a further planetary stage of the planetary gear mechanism.
 7. Theplanetary stage as claimed in claim 6, wherein the plug-in connection isconfigured as an external toothing system formed on the connecting ringand as an internal toothing system arranged on the internal gear or theplanetary gear carrier of the further planetary stage.
 8. The planetarystage as claimed in claim 1, wherein the planetary gear mechanism is acontinuous flow power plant gear mechanism.
 9. A wind power plant,comprising: a planetary stage of a planetary gear mechanism, theplanetary stage including: a gear mechanism housing including a fixedlyarranged internal gear, at least two planetary gears mounted in a planetspider having at least one cheek, and a sun gear, the planet spiderbeing connected to an input shaft, and a connection between the inputshaft and a component of a further planetary stage, the connection beingconfigured as a connecting web which is arranged in the region betweentwo planetary gears and within the internal gear and is connected to thecheek of the planet spider, the cheek being loaded by an introduction ofload/torque.
 10. The planetary stage as claimed in claim 8, wherein thecontinuous flow power plant gear mechanism is configured as an oceancurrent power plant gear mechanism or a wind power plant gear mechanism.